KARSYS hydrogeological 3D modeling of alpine karst aquifers developed in geologically complex areas: Picos de Europa National Park (Spain)

Karst aquifers are valuable groundwater resources whose management requires the use of functioning hydrogeological models. The KARSYS approach provides an explicit 3D conceptual model of the geometry and the functioning of karst aquifers that has been successfully applied in Swiss and Slovenian aquifers. In this work, KARSYS is applied in a complex geological area: the Picos de Europa National Park (Spain). The hydrogeological 3D model (500 km(2)) shows an alpine karst aquifer compartmentalized into 32 groundwater bodies dammed up by subvertical barriers creating elevated saturated zones (water tables at 1153 m asl) and lower ones (water tables at 145 m asl). The recharge is through 18 spring catchment areas. The groundwater flows to the saturated zones pass through vertical to inclined trajectories, and phreatic flows are oriented toward NW, NE and N. KARSYS can be applied to any geologically complex area at a regional scale, although the geological structure should be simplified and the precision in some places is low. Nevertheless, KARSYS helps to identify the hydrogeological behavior of karst areas and is a useful guide for future hydrogeological researches.